i. Field of the Invention
This invention relates to flammable fluid fuelled heaters and, in particular, although not necessarily solely, gas fuelled heaters which at least partially exhaust into a room in which they are housed.
ii. Description of the Prior Art
Traditional flammable fluid fuelled heaters such as a gas fuelled heater comprise a combustion and a flue to exhaust the products of that combustion externally of the room in which the unit is housed. The provision of such flues in a house or similar structure which does not have a provision for such a unit can provide difficulties and extra cost. Also, the flue exhausts heated air into the atmosphere wasting this quantity of heat produced by the heater.
Further, conventional gas fuelled heaters are often provided if the combustion chamber has been substantially enclosed other than air vents at the base of the article to draw air through the unit. Although some units exist having a substantially open front to the gas heater, the emissions from such a heater are in the order of 200 ppm of carbon monoxide into the room in which the unit is housed. This is undesirable from both a health risk in the build up of carbon monoxide and there is also an unpleasant smell from residual unburnt hydrocarbons.
In an attempt to reduce the emissions from such a gas fuelled heater having a substantially open front, the gas and oxygen mixture can be altered such that the combustion provides an invisible or blue flame. Although such a flame is cleaner in the emissions produced, it detracts from the visual aspects of the heater in which there is a desire to see a yellow flame such as would be produced in a typical log fireplace.
Further, some prior art designs for gas heaters are provided such as U.S. Pat. No. 1,884,746. The device described in this patent provides a catalytic converter in a secondary combustion chamber to reduce the quantity of carbon monoxide in the emissions. However, such a device relies on the use of incandescent or radiant tubes above the burner to, in addition to providing radiant heat towards the front of the apparatus, direct the emissions to a point high in the combustion chamber from which they can be directed through the catalytic converter to the outlet. If such an apparatus had the radiant tubes removed so as to provide a flame which is both yellow/orange in colour visible from the front of the unit excessive emissions may spill out the open front of the unit beyond levels desirable or, in some cases, allowable by law.